Ravenscroft did some voice-over work and singing for Disney in both the films and the attractions at Disneyland (which were later featured at Disney World). The most well known of these attractions are The Haunted Mansion, The Country Bear Jamboree, The Mark Twain Riverboat, The Pirates of the Caribbean and Walt Disney's Enchanted Tiki Room. His voice acting career began in 1940 and lasted until his death in 2005 at age 91.[2]

Ravenscroft sang bass on Rosemary Clooney's "This Ole House" which went to No. 1 in both the U.S. and Britain in 1954, as well as Stuart Hamblen's original version of that same song. He sang on the soundtrack for Ken Clark as "Stewpot" in South Pacific, one of the top-selling albums of the 1950s. Singing with the Johnny Mann Singers,[4] his distinctive bass can also be heard as part of the chorus on 28 of their albums that were released during the 1960s and 1970s. He was also the bass singer on Bobby Vee's 1960 Liberty hit record "Devil Or Angel". Andy Williams' recording of "The 12 Days of Christmas" features him as well. In the 1980s and 1990s, Ravenscroft was narrator for the annual Pageant of the Masters art show at the Laguna Beach, California, Festival of the Arts.

He sang the opening songs for the two Disney serials, used on The Mickey Mouse Club, Boys of the Western Sea, and The Hardy Boys: Mystery of the Applegate Treasure.

He sang the "Twitterpatter Song" and "Thumper's Song" on the Disneyland record Peter Cottontail and other Funny Bunnies.

On the Disneyland record All About Dragons, he both provided the narration and sang the songs "The Reluctant Dragon" and "The Loch Ness Monster".[5]

One of Ravenscroft's best-known uncredited works is as the vocalist for the song "You're a Mean One, Mr. Grinch." His name was accidentally left out of the credits, leading many to believe (erroneously) that the cartoon's narrator, Boris Karloff, sang the song, while others cited Tennessee Ernie Ford as the song's signature voice.[1]

For more than 50 years, he was the uncredited voice of Tony the Tiger for Kellogg's Frosted Flakes. His booming bass gave the cereal's tiger mascot a voice with the catchphrase "Good? They're grrrreat!"[8]

Various record companies, such as Abbott, Coral, Brunswick, and "X" (a division of RCA) also released singles by Ravenscroft, often in duets with little-known female vocalists, in an attempt to turn the bass-voiced veteran into a pop singer. These efforts were commercially unsuccessful, if often quite interesting. He was also teamed up with The Andrews Sisters (on the Dot Records album The Andrews Sisters Present) on the cover of Johnny Cymbal's "Mr. Bass Man". The Mellomen released some doo-wop records under the name Big John & the Buzzards, a name apparently given to them by the rock-and-roll-hating Mitch Miller.

Ravenscroft was married to June Ravenscroft in 1946, they had two children. June died in 1999 from unknown causes. Ravenscroft continued to voice Tony The Tiger through 2004, and also submitted to an interview that year by the Disney "Extinct Attractions Club" website. He died in his home on May 22, 2005 from prostate cancer. He was survived by his two children, Ron Ravenscroft and Nancy Ravenscroft. He was buried at the Memorial Gardens at the Crystal Cathedral in Garden Grove, California.[2]

In the June 6, 2005 issue of the ad-industry journal Advertising Age, Kellogg's ran an ad commemorating Ravenscroft. The headline read: "Behind every great character is an even greater man." After his death, Lee Marshall replaced him as the voice of Tony the Tiger in the Kellogg's commercials and some commercials recycle clips of Ravenscroft.